Digital broadband networking and communications products and services are the infrastructure over which the Internet operates. The universal benefits of the Internet are now quite well known, enabling immediate worldwide sharing of news and events, access to in-depth research on virtually any topic, sophisticated financial analysis available to all, the convenience of e-commerce available on virtually any product to consumers and the emerging capabilities for commercial e-commerce, and the outsourcing enabled by Application Service Providers and Storage Area Networks, to list just a few of the world-changing available uses.
This explosive growth in network traffic is further demonstrated by forecasts made by many leading networking industry experts regarding scaling specific infrastructure areas. Every aspect of these scaling estimates represents requirements for network equipment to scale to provide the necessary bandwidth. However, network traffic is susceptible to channel distortion. Often created by inherent networking equipment limitations, or by ambient electromagnetic fields, distortion can create bit errors within each transmitted data word. In a common bit error verification technique, each data word contains a checksum verifying the data in the transmission word. A transmitter then transmits the word, which is inspected by the receiver. If the checksum matches the arriving data word, the receiver presumes that the complete transmission was received, and a verified word is forwarded on to its destination. However, this process of performing checksum computation can also increase network latency since the transmitted word must be temporarily stored and verified in a memory buffer. In another possible solution, bandwidth is minimized to the greatest possible extent. In general, decreasing the amount of spectrum occupied by a signal also decreases the amount of transmitted noise. Reducing the bandwidth, however, can also increase the latency, since a greater amount of data may need to be buffered prior to being delivered to the receiving application.
To facilitate the description, FIG. 1 shows a simplified functional diagram of a common multilink communications channel. In general, a channel is a separate path along which a data word can be transmitted. Each channel further comprises a set of links through which individual data bits can simultaneously flow, and in some instances, the links can be redundant links. Channel 106 comprises N number of links 104 and is coupled to a transmitter 102 and a receiver 108. For example, in a redundant two-link communications channel, two identical words would be transmitted from transmitter 102 across channel 106 to receiver 108. The receiver contains a store and forward buffer 110, for temporarily storing and evaluating the received words. These words are subsequently forwarded on to the appropriate destination, before the next set of words is transmitted. If one of the words is deemed to be invalid, the valid word is the one that is forwarded. This redundant technique works well, but does not overcome the limitations of bandwidth and latency described above.
What are needed is both a method and an apparatus for verifying the transmission of a set of data bits from a transmitter to a receiver, without decreasing bandwidth or increasing latency.